////////////////////////////////////////////////////////////
// ==== HTML5 CANVAS transform Image ====
// full 3D version
// @author Gerard Ferrandez / http://www.dhteumeuleu.com/
// last update: Dec 8, 2012
// Released under the MIT license
// http://www.dhteumeuleu.com/LICENSE.html
////////////////////////////////////////////////////////////

"use strict";
// import {ge1doot} from "./ge1doot.js"

// var ge1doot = ge1doot || {};
// ge1doot.transform3D = {};

// /* ==== draw Poly ==== */
// ge1doot.transform3D.drawPoly = function () {
// 	this.ctx.beginPath();
// 	this.ctx.moveTo(this.points[0].X, this.points[0].Y);
// 	this.ctx.lineTo(this.points[1].X, this.points[1].Y);
// 	this.ctx.lineTo(this.points[2].X, this.points[2].Y);
// 	this.ctx.lineTo(this.points[3].X, this.points[3].Y);
// 	this.ctx.closePath();
// }
// /* =============== camera constructor ================= */
// ge1doot.transform3D.Camera = function (setup, func) {
// 	ge1doot.camera = this;
// 	this.x  = 0;
// 	this.y  = 0;
// 	this.z  = 0;
// 	this.rx = 0;
// 	this.ry = 0;
// 	this.rz = 0;
// 	this.focalLength     = setup.focalLength || 500;
// 	this.easeTranslation = setup.easeTranslation || 0.1;
// 	this.easeRotation    = setup.easeRotation || 0.025;
// 	this.enableRx        = setup.disableRx ? false : true;
// 	this.enableRy        = setup.disableRy ? false : true;
// 	this.enableRz        = setup.disableRz ? false : true;
// 	this.cmov = false;
// 	this.cosX = 1;
// 	this.sinX = 0;
// 	this.cosY = 1;
// 	this.sinY = 0;
// 	this.cosZ = 1;
// 	this.sinZ = 0;
// 	this.target = {
// 		over: false,
// 		elem: false,
// 		x:  0,
// 		y:  0,
// 		z:  0,
// 		rx: 0,
// 		ry: 0,
// 		rz: 0
// 	};
// 	// ---- def custom move ----
// 	if (func && func.move) this.cmov = func.move;
// }
// /* ==== easing ==== */
// ge1doot.transform3D.Camera.prototype.ease = function (target, value) {
// 	while (Math.abs(target - value) > Math.PI) {
// 		if (target < value)  value -= 2 * Math.PI;
// 		else value += 2 * Math.PI;
// 	}
// 	return (target - value) * this.easeRotation;
// }
// /* ==== move / rotate camera ==== */
// ge1doot.transform3D.Camera.prototype.move = function () {
// 	// ---- run custom function ----
// 	this.cmov && this.cmov();
// 	// ---- translations ----
// 	this.x += (this.target.x - this.x) * this.easeTranslation;
// 	this.y += (this.target.y - this.y) * this.easeTranslation;
// 	this.z += (this.target.z - this.z) * this.easeTranslation;
// 	// ---- rotation rx ----
// 	if (this.enableRx) {
// 		this.rx += this.ease(this.target.rx, this.rx);
// 		this.cosX = Math.cos(this.rx);
// 		this.sinX = Math.sin(this.rx);
// 	}
// 	// ---- rotation ry ----
// 	if (this.enableRy) {
// 		this.ry += this.ease(this.target.ry, this.ry);
// 		this.cosY = Math.cos(this.ry);
// 		this.sinY = Math.sin(this.ry);
// 	}
// 	// ---- rotation rz ----
// 	if (this.enableRz) {
// 		this.rz += this.ease(this.target.rz, this.rz);
// 		this.cosZ = Math.cos(this.rz);
// 		this.sinZ = Math.sin(this.rz);
// 	}
// }
// /* =============== point constructor ================= */
// ge1doot.transform3D.Point = function (x, y, z, tx, ty) {
// 	this.x = x;
// 	this.y = y;
// 	this.z = z;
// 	this.tx = tx || 0;
// 	this.ty = ty || 0;
// 	this.visible = false;
// 	this.scale = 0;
// 	this.X = 0;
// 	this.Y = 0;
// 	this.Z = 0;
// 	this.next = true;
// }
// /* ==== perspective projection ==== */
// ge1doot.transform3D.Point.prototype.projection = function () {
// 	var sw       = this.scr.width  >> 1;
// 	var sh       = this.scr.height >> 1;
// 	// ---- 3D coordinates ----
// 	var nx       = this.x - this.camera.x;
// 	var ny       = this.y - this.camera.y;
// 	var nz       = this.z - this.camera.z;
// 	// ---- 3D rotation and projection ----
// 	if (this.camera.enableRz) {
// 		var u = this.camera.sinZ * ny + this.camera.cosZ * nx;
// 		var t = this.camera.cosZ * ny - this.camera.sinZ * nx;
// 	} else {
// 		var u = nx;
// 		var t = ny;
// 	}
// 	var s        = this.camera.cosY * nz + this.camera.sinY * u;
// 	this.Z       = this.camera.cosX * s  - this.camera.sinX * t;
// 	this.scale   = this.camera.focalLength / Math.max(1, this.Z);
// 	this.X       = sw + (this.camera.cosY * u  - this.camera.sinY * nz) * this.scale;
// 	this.Y       = -(this.camera.y >> 1) + sh - (this.camera.sinX * s  + this.camera.cosX * t) * this.scale;
// 	// ---- visibility test ----
// 	this.visible = (
// 		this.X > -sw * 0.5 && this.X < sw * 2.5
// 	) && (
// 		this.Y > -sh * 0.5 && this.Y < sh * 2.5
// 	);
// 	// ----return next (fast loop) ----
// 	return this.next;
// }
// /* ==== triangle constructor ==== */
// ge1doot.transform3D.Triangle = function (parent, p0, p1, p2) {
// 	this.ctx = parent.ctx;
// 	this.texture = parent.texture;
// 	this.p0  = p0;
// 	this.p1  = p1;
// 	this.p2  = p2;
// 	this.d   = p0.tx * (p2.ty - p1.ty) - p1.tx * p2.ty + p2.tx * p1.ty + (p1.tx - p2.tx) * p0.ty;
// 	this.pmy = p1.ty - p2.ty;
// 	this.pmx = p1.tx - p2.tx;
// 	this.pxy = p2.tx * p1.ty - p1.tx * p2.ty;
// 	if (parent.t) parent.t.next = true;
// }
// /* ==== draw triangle ==== */
// ge1doot.transform3D.Triangle.prototype.draw = function () {
// 	if (this.p0.visible || this.p1.visible || this.p2.visible) {
// 		var dx, dy, d;
// 		// ---- centroid ----
// 		var xc = (this.p0.X + this.p1.X + this.p2.X) / 3;
// 		var yc = (this.p0.Y + this.p1.Y + this.p2.Y) / 3;
// 		// ---- clipping ----
// 		this.ctx.save();
// 		this.ctx.beginPath();
// 		dx = xc - this.p0.X;
// 		dy = yc - this.p0.Y;
// 		d = Math.max(Math.abs(dx), Math.abs(dy));
// 		this.ctx.moveTo(this.p0.X - 2 * (dx / d), this.p0.Y - 2 * (dy / d));
// 		dx = xc - this.p1.X;
// 		dy = yc - this.p1.Y;
// 		d = Math.max(Math.abs(dx), Math.abs(dy));
// 		this.ctx.lineTo(this.p1.X - 2 * (dx / d), this.p1.Y - 2 * (dy / d));
// 		dx = xc - this.p2.X;
// 		dy = yc - this.p2.Y;
// 		d = Math.max(Math.abs(dx), Math.abs(dy));
// 		this.ctx.lineTo(this.p2.X - 2 * (dx / d), this.p2.Y - 2 * (dy / d));
// 		this.ctx.closePath();
// 		this.ctx.clip();
// 		// ---- transform ----
// 		var t0 = this.p2.X  - this.p1.X,
// 			t1 = this.p1.Y  - this.p2.Y,
// 			t2 = this.p2.ty * this.p1.X,
// 			t3 = this.p1.tx * this.p2.X,
// 			t4 = this.p2.ty * this.p1.Y,
// 			t5 = this.p1.ty * this.p2.X,
// 			t6 = this.p1.ty * this.p2.Y,
// 			t7 = this.p2.tx * this.p1.X,
// 			t8 = this.p1.tx * this.p2.Y,
// 			t9 = this.p2.tx * this.p1.Y;
// 		this.ctx.transform(
// 			-(this.p0.ty * t0 - t5 + t2 + this.pmy * this.p0.X) / this.d, // m11
// 			 (t6 + this.p0.ty * t1 - t4 - this.pmy * this.p0.Y) / this.d, // m12
// 			 (this.p0.tx * t0 - t3 + t7 + this.pmx * this.p0.X) / this.d, // m21
// 			-(t8 + this.p0.tx * t1 - t9 - this.pmx * this.p0.Y) / this.d, // m22
// 			 (this.p0.tx * (t2 - t5) + this.p0.ty * (t3 - t7) + this.pxy * this.p0.X) / this.d, // dx
// 			 (this.p0.tx * (t4 - t6) + this.p0.ty * (t8 - t9) + this.pxy * this.p0.Y) / this.d  // dy
// 		);
// 		// ---- draw ----
// 		this.ctx.drawImage(this.texture, 0, 0);
// 		this.ctx.restore();
// 	}
// 	return this.next;
// }
// /* ===================== image constructor ========================== */
// ge1doot.transform3D.Image = function (parent, imgSrc, lev, callback) {
// 	this.parent        = parent;
// 	this.points        = [];
// 	this.triangles     = [];
// 	this.ctx           = ge1doot.screen.ctx;
// 	this.pointer       = ge1doot.pointer;
// 	this.texture       = new Image();
// 	this.texture.src   = imgSrc;
// 	this.isLoading     = true;
// 	this.callback      = callback;
// 	this.textureWidth  = 0;
// 	this.textureHeight = 0;
// 	this.level         = lev || 1;
// 	this.visible       = false;
// 	this.t             = false;
// 	if (!ge1doot.transform3D.Point.prototype.scr) {
// 		ge1doot.transform3D.Point.prototype.scr    = ge1doot.screen;
// 		ge1doot.transform3D.Point.prototype.camera = ge1doot.camera;
// 	}
// }
// /* ==== drawPoly prototype ==== */
// ge1doot.transform3D.Image.prototype.drawPoly = ge1doot.transform3D.drawPoly;
// /* ==== change tessellation level prototype ==== */
// ge1doot.transform3D.Image.prototype.setLevel = function (level) {
// 	this.points.length = 0;
// 	this.triangles.length = 0;
// 	this.level = level;
// 	this.loading();
// }
// /* ==== loading prototype ==== */
// ge1doot.transform3D.Image.prototype.loading = function () {
// 	if (this.texture.complete) {
// 		var dir = [0,1,1,0,0,0,1,1];
// 		this.isLoading = false;
// 		// ---- image size ----
// 		this.textureWidth = this.texture.width;
// 		this.textureHeight = this.texture.height;
// 		// ---- isLoaded callback ---
// 		this.callback && this.callback.isLoaded && this.callback.isLoaded(this);
// 		// ---- texture position ----
// 		for (var i = -1, p; p = this.points[++i];) {
// 			p.tx = this.textureWidth  * dir[i];
// 			p.ty = this.textureHeight * dir[i+4];
// 		}
// 		// ---- triangularization ----
// 		this.triangulate(this.points[0], this.points[1], this.points[2], this.level);
// 		this.triangulate(this.points[0], this.points[2], this.points[3], this.level);
// 		// ---- last point ----
// 		this.points[this.points.length - 1].next = false;
// 	}
// }
// /* ==== vector bisection function ==== */
// ge1doot.transform3D.Image.prototype.subdivise = function (p0, p1) {
// 	return {
// 		x:  (p1.x + p0.x)   * 0.5,
// 		y:  (p1.y + p0.y)   * 0.5,
// 		z:  (p1.z + p0.z)   * 0.5,
// 		tx: (p1.tx + p0.tx) * 0.5,
// 		ty: (p1.ty + p0.ty) * 0.5
// 	};
// }
// /* ==== triangulation ==== */
// ge1doot.transform3D.Image.prototype.triangulate = function (p0, p1, p2, level) {
// 	level--;
// 	if (level === 0) {
// 		// final triangle
// 		this.t = new ge1doot.transform3D.Triangle(this, p0, p1, p2);
// 		this.triangles.push(this.t);
// 	} else {
// 		// ---- subdivision ----
// 		var p01 = this.subdivise(p0, p1);
// 		var p12 = this.subdivise(p1, p2);
// 		var p20 = this.subdivise(p2, p0);
// 		// ---- insert new points ----
// 		this.points.push(p01 = new ge1doot.transform3D.Point(p01.x, p01.y, p01.z, p01.tx, p01.ty));
// 		this.points.push(p12 = new ge1doot.transform3D.Point(p12.x, p12.y, p12.z, p12.tx, p12.ty));
// 		this.points.push(p20 = new ge1doot.transform3D.Point(p20.x, p20.y, p20.z, p20.tx, p20.ty));
// 		// ---- recursive triangulation ----
// 		this.triangulate(p0,   p01,  p20, level);
// 		this.triangulate(p01,  p1,   p12, level);
// 		this.triangulate(p20,  p12,  p2,  level);
// 		this.triangulate(p01,  p12,  p20, level);
// 	}
// }
// /* ==== transform prototype ==== */
// ge1doot.transform3D.Image.prototype.transform3D = function (backfaceTest) {
// 	if (this.isLoading) {
// 		// ---- image is loading ----
// 		this.loading();
// 		return false;
// 	} else {
// 		// ---- project points ----
// 		for (
// 			var i = 0;
// 			this.points[i++].projection();
// 		);
// 		if (backfaceTest) {
// 			var p0 = this.points[0];
// 			var p1 = this.points[1];
// 			var p2 = this.points[2];
// 			return (
// 				((p1.Y - p0.Y) / (p1.X - p0.X) - 
// 				(p2.Y - p0.Y) / (p2.X - p0.X) < 0) ^ 
// 				(p0.X <= p1.X == p0.X > p2.X)
// 			);
// 		} else return true;
// 	}
// }
// /* ==== draw prototype ==== */
// ge1doot.transform3D.Image.prototype.draw = function () {
// 	if (!this.isLoading) {
// 		// ---- draw triangles ----
// 		for (
// 			var i = 0;
// 			this.triangles[i++].draw();
// 		);
// 	}
// }
// /* ==== isPointerInside prototype ==== */
// ge1doot.transform3D.Image.prototype.isPointerInside = function (x, y) {
// 	this.drawPoly(this.points);
// 	return this.ctx.isPointInPath(x, y);
// }

var transform3D = (ge1doot) => {
	ge1doot = ge1doot || {};
	ge1doot.transform3D = {};
	
	/* ==== draw Poly ==== */
	ge1doot.transform3D.drawPoly = function () {
		this.ctx.beginPath();
		this.ctx.moveTo(this.points[0].X, this.points[0].Y);
		this.ctx.lineTo(this.points[1].X, this.points[1].Y);
		this.ctx.lineTo(this.points[2].X, this.points[2].Y);
		this.ctx.lineTo(this.points[3].X, this.points[3].Y);
		this.ctx.closePath();
	}
	/* =============== camera constructor ================= */
	ge1doot.transform3D.Camera = function (setup, func) {
		ge1doot.camera = this;
		this.x  = 0;
		this.y  = 0;
		this.z  = 0;
		this.rx = 0;
		this.ry = 0;
		this.rz = 0;
		this.focalLength     = setup.focalLength || 500;
		this.easeTranslation = setup.easeTranslation || 0.1;
		this.easeRotation    = setup.easeRotation || 0.025;
		this.enableRx        = setup.disableRx ? false : true;
		this.enableRy        = setup.disableRy ? false : true;
		this.enableRz        = setup.disableRz ? false : true;
		this.cmov = false;
		this.cosX = 1;
		this.sinX = 0;
		this.cosY = 1;
		this.sinY = 0;
		this.cosZ = 1;
		this.sinZ = 0;
		this.target = {
			over: false,
			elem: false,
			x:  0,
			y:  0,
			z:  0,
			rx: 0,
			ry: 0,
			rz: 0
		};
		// ---- def custom move ----
		if (func && func.move) this.cmov = func.move;
	}
	/* ==== easing ==== */
	ge1doot.transform3D.Camera.prototype.ease = function (target, value) {
		while (Math.abs(target - value) > Math.PI) {
			if (target < value)  value -= 2 * Math.PI;
			else value += 2 * Math.PI;
		}
		return (target - value) * this.easeRotation;
	}
	/* ==== move / rotate camera ==== */
	ge1doot.transform3D.Camera.prototype.move = function () {
		// ---- run custom function ----
		this.cmov && this.cmov();
		// ---- translations ----
		this.x += (this.target.x - this.x) * this.easeTranslation;
		this.y += (this.target.y - this.y) * this.easeTranslation;
		this.z += (this.target.z - this.z) * this.easeTranslation;
		// ---- rotation rx ----
		if (this.enableRx) {
			this.rx += this.ease(this.target.rx, this.rx);
			this.cosX = Math.cos(this.rx);
			this.sinX = Math.sin(this.rx);
		}
		// ---- rotation ry ----
		if (this.enableRy) {
			this.ry += this.ease(this.target.ry, this.ry);
			this.cosY = Math.cos(this.ry);
			this.sinY = Math.sin(this.ry);
		}
		// ---- rotation rz ----
		if (this.enableRz) {
			this.rz += this.ease(this.target.rz, this.rz);
			this.cosZ = Math.cos(this.rz);
			this.sinZ = Math.sin(this.rz);
		}
	}
	/* =============== point constructor ================= */
	ge1doot.transform3D.Point = function (x, y, z, tx, ty) {
		this.x = x;
		this.y = y;
		this.z = z;
		this.tx = tx || 0;
		this.ty = ty || 0;
		this.visible = false;
		this.scale = 0;
		this.X = 0;
		this.Y = 0;
		this.Z = 0;
		this.next = true;
	}
	/* ==== perspective projection ==== */
	ge1doot.transform3D.Point.prototype.projection = function () {
		var sw       = this.scr.width  >> 1;
		var sh       = this.scr.height >> 1;
		// ---- 3D coordinates ----
		var nx       = this.x - this.camera.x;
		var ny       = this.y - this.camera.y;
		var nz       = this.z - this.camera.z;
		// ---- 3D rotation and projection ----
		if (this.camera.enableRz) {
			var u = this.camera.sinZ * ny + this.camera.cosZ * nx;
			var t = this.camera.cosZ * ny - this.camera.sinZ * nx;
		} else {
			var u = nx;
			var t = ny;
		}
		var s        = this.camera.cosY * nz + this.camera.sinY * u;
		this.Z       = this.camera.cosX * s  - this.camera.sinX * t;
		this.scale   = this.camera.focalLength / Math.max(1, this.Z);
		this.X       = sw + (this.camera.cosY * u  - this.camera.sinY * nz) * this.scale;
		this.Y       = -(this.camera.y >> 1) + sh - (this.camera.sinX * s  + this.camera.cosX * t) * this.scale;
		// ---- visibility test ----
		this.visible = (
			this.X > -sw * 0.5 && this.X < sw * 2.5
		) && (
			this.Y > -sh * 0.5 && this.Y < sh * 2.5
		);
		// ----return next (fast loop) ----
		return this.next;
	}
	/* ==== triangle constructor ==== */
	ge1doot.transform3D.Triangle = function (parent, p0, p1, p2) {
		this.ctx = parent.ctx;
		this.texture = parent.texture;
		this.p0  = p0;
		this.p1  = p1;
		this.p2  = p2;
		this.d   = p0.tx * (p2.ty - p1.ty) - p1.tx * p2.ty + p2.tx * p1.ty + (p1.tx - p2.tx) * p0.ty;
		this.pmy = p1.ty - p2.ty;
		this.pmx = p1.tx - p2.tx;
		this.pxy = p2.tx * p1.ty - p1.tx * p2.ty;
		if (parent.t) parent.t.next = true;
	}
	/* ==== draw triangle ==== */
	ge1doot.transform3D.Triangle.prototype.draw = function () {
		if (this.p0.visible || this.p1.visible || this.p2.visible) {
			var dx, dy, d;
			// ---- centroid ----
			var xc = (this.p0.X + this.p1.X + this.p2.X) / 3;
			var yc = (this.p0.Y + this.p1.Y + this.p2.Y) / 3;
			// ---- clipping ----
			this.ctx.save();
			this.ctx.beginPath();
			dx = xc - this.p0.X;
			dy = yc - this.p0.Y;
			d = Math.max(Math.abs(dx), Math.abs(dy));
			this.ctx.moveTo(this.p0.X - 2 * (dx / d), this.p0.Y - 2 * (dy / d));
			dx = xc - this.p1.X;
			dy = yc - this.p1.Y;
			d = Math.max(Math.abs(dx), Math.abs(dy));
			this.ctx.lineTo(this.p1.X - 2 * (dx / d), this.p1.Y - 2 * (dy / d));
			dx = xc - this.p2.X;
			dy = yc - this.p2.Y;
			d = Math.max(Math.abs(dx), Math.abs(dy));
			this.ctx.lineTo(this.p2.X - 2 * (dx / d), this.p2.Y - 2 * (dy / d));
			this.ctx.closePath();
			this.ctx.clip();
			// ---- transform ----
			var t0 = this.p2.X  - this.p1.X,
				t1 = this.p1.Y  - this.p2.Y,
				t2 = this.p2.ty * this.p1.X,
				t3 = this.p1.tx * this.p2.X,
				t4 = this.p2.ty * this.p1.Y,
				t5 = this.p1.ty * this.p2.X,
				t6 = this.p1.ty * this.p2.Y,
				t7 = this.p2.tx * this.p1.X,
				t8 = this.p1.tx * this.p2.Y,
				t9 = this.p2.tx * this.p1.Y;
			this.ctx.transform(
				-(this.p0.ty * t0 - t5 + t2 + this.pmy * this.p0.X) / this.d, // m11
				 (t6 + this.p0.ty * t1 - t4 - this.pmy * this.p0.Y) / this.d, // m12
				 (this.p0.tx * t0 - t3 + t7 + this.pmx * this.p0.X) / this.d, // m21
				-(t8 + this.p0.tx * t1 - t9 - this.pmx * this.p0.Y) / this.d, // m22
				 (this.p0.tx * (t2 - t5) + this.p0.ty * (t3 - t7) + this.pxy * this.p0.X) / this.d, // dx
				 (this.p0.tx * (t4 - t6) + this.p0.ty * (t8 - t9) + this.pxy * this.p0.Y) / this.d  // dy
			);
			// ---- draw ----
			this.ctx.drawImage(this.texture, 0, 0);
			this.ctx.restore();
		}
		return this.next;
	}
	/* ===================== image constructor ========================== */
	ge1doot.transform3D.Image = function (parent, imgSrc, lev, callback) {
		this.parent        = parent;
		this.points        = [];
		this.triangles     = [];
		this.ctx           = ge1doot.screen.ctx;
		this.pointer       = ge1doot.pointer;
		this.texture       = new Image();
		this.texture.src   = imgSrc;
		this.isLoading     = true;
		this.callback      = callback;
		this.textureWidth  = 0;
		this.textureHeight = 0;
		this.level         = lev || 1;
		this.visible       = false;
		this.t             = false;
		if (!ge1doot.transform3D.Point.prototype.scr) {
			ge1doot.transform3D.Point.prototype.scr    = ge1doot.screen;
			ge1doot.transform3D.Point.prototype.camera = ge1doot.camera;
		}
	}
	/* ==== drawPoly prototype ==== */
	ge1doot.transform3D.Image.prototype.drawPoly = ge1doot.transform3D.drawPoly;
	/* ==== change tessellation level prototype ==== */
	ge1doot.transform3D.Image.prototype.setLevel = function (level) {
		this.points.length = 0;
		this.triangles.length = 0;
		this.level = level;
		this.loading();
	}
	/* ==== loading prototype ==== */
	ge1doot.transform3D.Image.prototype.loading = function () {
		if (this.texture.complete) {
			var dir = [0,1,1,0,0,0,1,1];
			this.isLoading = false;
			// ---- image size ----
			this.textureWidth = this.texture.width;
			this.textureHeight = this.texture.height;
			// ---- isLoaded callback ---
			this.callback && this.callback.isLoaded && this.callback.isLoaded(this);
			// ---- texture position ----
			for (var i = -1, p; p = this.points[++i];) {
				p.tx = this.textureWidth  * dir[i];
				p.ty = this.textureHeight * dir[i+4];
			}
			// ---- triangularization ----
			this.triangulate(this.points[0], this.points[1], this.points[2], this.level);
			this.triangulate(this.points[0], this.points[2], this.points[3], this.level);
			// ---- last point ----
			this.points[this.points.length - 1].next = false;
		}
	}
	/* ==== vector bisection function ==== */
	ge1doot.transform3D.Image.prototype.subdivise = function (p0, p1) {
		return {
			x:  (p1.x + p0.x)   * 0.5,
			y:  (p1.y + p0.y)   * 0.5,
			z:  (p1.z + p0.z)   * 0.5,
			tx: (p1.tx + p0.tx) * 0.5,
			ty: (p1.ty + p0.ty) * 0.5
		};
	}
	/* ==== triangulation ==== */
	ge1doot.transform3D.Image.prototype.triangulate = function (p0, p1, p2, level) {
		level--;
		if (level === 0) {
			// final triangle
			this.t = new ge1doot.transform3D.Triangle(this, p0, p1, p2);
			this.triangles.push(this.t);
		} else {
			// ---- subdivision ----
			var p01 = this.subdivise(p0, p1);
			var p12 = this.subdivise(p1, p2);
			var p20 = this.subdivise(p2, p0);
			// ---- insert new points ----
			this.points.push(p01 = new ge1doot.transform3D.Point(p01.x, p01.y, p01.z, p01.tx, p01.ty));
			this.points.push(p12 = new ge1doot.transform3D.Point(p12.x, p12.y, p12.z, p12.tx, p12.ty));
			this.points.push(p20 = new ge1doot.transform3D.Point(p20.x, p20.y, p20.z, p20.tx, p20.ty));
			// ---- recursive triangulation ----
			this.triangulate(p0,   p01,  p20, level);
			this.triangulate(p01,  p1,   p12, level);
			this.triangulate(p20,  p12,  p2,  level);
			this.triangulate(p01,  p12,  p20, level);
		}
	}
	/* ==== transform prototype ==== */
	ge1doot.transform3D.Image.prototype.transform3D = function (backfaceTest) {
		if (this.isLoading) {
			// ---- image is loading ----
			this.loading();
			return false;
		} else {
			// ---- project points ----
			for (
				var i = 0;
				this.points[i++].projection();
			);
			if (backfaceTest) {
				var p0 = this.points[0];
				var p1 = this.points[1];
				var p2 = this.points[2];
				return (
					((p1.Y - p0.Y) / (p1.X - p0.X) - 
					(p2.Y - p0.Y) / (p2.X - p0.X) < 0) ^ 
					(p0.X <= p1.X == p0.X > p2.X)
				);
			} else return true;
		}
	}
	/* ==== draw prototype ==== */
	ge1doot.transform3D.Image.prototype.draw = function () {
		if (!this.isLoading) {
			// ---- draw triangles ----
			for (
				var i = 0;
				this.triangles[i++].draw();
			);
		}
	}
	/* ==== isPointerInside prototype ==== */
	ge1doot.transform3D.Image.prototype.isPointerInside = function (x, y) {
		this.drawPoly(this.points);
		return this.ctx.isPointInPath(x, y);
	}
}

export {
	transform3D
}